圆坯连铸过程中结晶器内坯壳热应力模拟

Numerical Simulation of Thermal Stress Field for Shell in Crystallizer During Round Billet Continuous Casting

铸件铸造过程热应力分析是铸件凝固过程数值模拟的重要组成部分,对于优化铸件的工艺设计、分析铸件凝固冷却过程中温度场变化引起的应力变化趋势,提高铸件质量有重要作用。本文应用ANSYS软件,对圆坯连铸过程结晶器内逐渐凝固形成的坯壳进行了热应力模拟,分析了拉坯速度、热流边界条件、圆坯尺寸以及浇注温度对结晶器出口处铸坯质量的影响。结果表明,冷却效果好,坯壳易形成,厚度较厚,但冷却中铸坯的温度梯度较大,结晶器出口处的最大等效应力值高。同时,结晶器出口处的坯壳厚度随浇注温度的升高而变薄。

Thermal stress analysis during casting process is an important part of the numerical simulation of solidication process of castings. It plays a vital role in the trend analysis of residual stress caused by changing temperature field during the billet cooling and optimizing process design. ANSYS was used to carry out the thermal-stress analysis of the gradually solidified shell in the crystallizer during round billet continuous casting process based on finite element method. Influences of casting speed, heat flux boundary conditions, round billet size and the pouring temperature on the slab quality of the crystallizer exit were analyzed. The results show that the cooling effect is better, the shell is thicker and formed more easily. But the temperature gradient of the billet is larger during cooling and the maximum equivalent stress value is higher in the crystallizer exit. At the same time, the thickness of the shell of the crystallizer exit is thinner with the increase of pouring temperature.